[enra]

One benefit can be that you access / pay with Amex points, which I think Stripe doesn't offer.

Also I've seen Amex offer login/auth verification, where you a service can verify you as the actual Amex user, and possibly trust you more that way.

[wil421]

I booked some museum visits in Italy this past summer. On a few of the sites I'd be sent to AMEX and enter some verification codes before the payment would process.

Never seen it in the US but it would be nice. I feel more comfortable going directly to AMEX first. Some website payment systems are shady feeling.